Field of the Disclosure
The present invention relates to a combo antenna unit and a wireless power receiving module including the same.
Description of the Related Art
Recently, various functions including radio frequency identification (RFID), near field communication (NFC), a wireless charger, an interactive pen tablet and the like are added to portable terminals including mobile phones and tablet Personal Computers.
NFC is one of RFID, which is an electronic tag, and refers to a technology for transferring data between terminal devices within a short range of 10 cm by using a non-contact short-range wireless communication module using a frequency band of 13.56 MHz. NFC is extensively used for mobile payment as well as a file transfer method of transferring goods information at a supermarket or a general store, or travel information for visitors, traffic information, access control and locking devices, and the like.
In addition, according to the latest Google's announcement, the “Android Beam” equipped with smartphones provides the ability to transfer photos, business cards, files, maps, web sites, etc., as well as mobile payment, as NFC-based local area information transmission and reception functions, from one phone to another phone.
Meanwhile, a portable terminal has a wireless charging function for wirelessly charging a built-in battery. The wireless charging function is performed by a wireless power receiving module built in the portable terminal, and a wireless power transmitting module for supplying power to the wireless power receiving module. In recent years, the thickness of the wireless power receiving module built in the portable terminal has been reduced as the size of the portable terminal has been reduced. For example, the total thickness of the wireless power receiving module is designed to be equal to or less 0.6 m, or even equal to or less 0.3 mm.
When the thickness of the wireless power receiving module is designed to be equal to or less 0.6 mm, or even equal to or less 0.3 mm, it is difficult to realize the characteristics required for the wireless charging function. Accordingly, in order to satisfy the required characteristics at the limited thickness, it is necessary to reduce the overall thickness of a shielding unit, or to reduce the thickness of a radiator constituting the antenna.
However, if the thickness of the shielding unit is reduced, there is a problem that the charging efficiency is deteriorated due to reduction of the shielding performance of a magnetic field. If the thickness of the radiator constituting the antenna, especially the radiator constituting the wireless power transmission antenna, is reduced, a resistance is increased by reduction of cross-sectional area of the radiator. Thus, the charging efficiency is deteriorated, and heat is generated.
In general, a plurality of radiators is formed on a surface of a circuit board as a pattern to constitute the antennas. However, using the circuit board causes increase of cost of the final product because the production cost of the circuit board is relatively higher than that of other components.